Incandescent-lamp filament



(No Model.)

T. A. EDISON. INGANDESGENT LAMP PILAMENT.

Patented Jan. 8, 1889 AT TEST:

UNITED STATES PATENT EEtcE,

THOMAS A. EDISON, OF MENLO PARK, XEIV JERSEY.

lNCANDESCENT-LAMP FlLAMENT.

SPECIFICATION forming part of Letters Patent No. 395,963, dated January 8, 1889. Application filed April 5, 1884. Serial No. 126,802. (No specimens.

T0 (LU whom it nmy concern/.-

Be it known that I, Tnonas A. EDISON, of Menlo Park, in the county of Middlesex. and State of New Jersey, have invented a new and useful Improvement in Incandescing Conductors t'orElectric Lamps, (Case No. il 7,)

terial in a vacuum by electrical heating and l causing it to be deposited from the vapor upon any object in the vacuum.

For the purposes of the present invention I either deposit carbon, silicon, boron, osmium,

in sheets, from which filaments for the incandescing conductors are cut, stamped, or otherwise formed; or I deposit the material directly in the filamentary form.

ithin the vacuum-chaml)er, which is exhausted in any suitable manner, I place one or more plates of polished glass of suitable size, each preferably having a coating of a form, the rest of the deposit being intercepted by the screen.

In the accompanying drawings, Figure l. represents an apparatus which may be conveniently employed. Fig. 2 is an enlarged view of a filament cut from a sheet, and I} a view of one of the screens used in depositing the filaments directly.

A is the bell-jar of an air-pump.

B B are glass plates held by suitable supports.

To the lectrodes 1 of carbon or silicon circuit-wires I 2 lead from any suitable source of electric energy. The two electrodes are so placed that an arc is termed between them by the current, and the deposit proceeding in straight lines therefrom is formed evenly upon all parts of theplates. It is then stripped f off in sheets, from which the soluble material,

if such is used, is removed, and filaments C are readily formed by cutting or punching. or other refractory high-resistance material material. soluble in water or alcohol such as i formed upon the plates to any desired llllClE ness, which may readily be s1 ripped oil", and

tenacious, flexible sheets of the carbon, silicon, or other material.

I may, however, interposc a screen, I), be tween the arc and the plate, having apertures Z) I), through which apertures the deposit is made in the shape of a straight strip with enlarged ends, which may be bent into the loop form. In this way filaments of silicon may be formed, which it has heretofore been difficult to produce.

I am aware that it has been noticed as a scientific fact that films of gold will be deposited on the walls of Geissler tubes when that metal. is subjected to the action of the electrical discharge in such tubes.

\Vhat I claim is- The process ot preparing material for the manufacture of filaments for incandescent electric lamps, consisting in volatilizing a subst ancc having a high electrical resistance by the soluble material is then removed. leaving electrically heating such substance in a vacuum, causing such substance to be deposited From these sheets the flexible filaments are formed in the desired 5 shape. To form the filaments directly, a screen of suitable material provided with one or more apertures of the shape and size desired for the filament is interposed between in the 't'orm ol' filaments or as a sheet from which filaments are formed, substantially as set forth.

This specification signed and witnessed this 22d day of January, 1884.

THOS. A. EDISON. \Vitnesses:

A. W. KIDDLE, E. C. ROWLAND. 

